Imaging with the 130pds

[sagramore]

Hi Carole. Congrats on the fight image, it's nice to have something to look at after all the stress of getting things just right isn't it?

I have seen similar things to the "cloud" when I'm shooting close to a full moon - I think they're stray internal reflections that you would normally never see but the full moon is bright enough to really push them through. I have similar problems with a local street light that stops me being able to image in one direction at all. Perhaps it's time I bit the bullet and tried flocking?

I certainly wouldn't let that worry me until I tried a shot away from the brightness of the moon though. If it's still present in dark sky then further investigation might be necessary!

[carastro]

Thanks Sagramore.  Going to clean that coma corrector before the next imaging attempt.  I only bought it that evening and went from SE london to SW London to get it as I wanted to be sure it would all fit.  When I got home it was around 11pm, and it was a clear sky.  I was too impatient to see where focus would be and how far the focusser would encroach into the OTA to stop and clean the CC first.  

Not had a clear night since, so would have still been waiting and wondering if I hadn't gone out then. 

Just need a clear night now without that pesky Moon.  

Carole 

 

[dyfiastro]

So I set about stripping and sorting the scope tonight.
Stripping it down was pretty easy apart from getting the primary mirror cell out which proved to be harder than I am sure it should have been.
Once it was stripped I gave the inside of the tube a good clean down with some nail varnish remover to get rid of any residue ready for the flocking. I was pretty surprised by just how reflective the standard coating actually was once I got it under the light.

I decided to flock the tube in strips which worked out pretty well with only a few small gaps.
 

I also set about flocking both the outside and the inside of the focuser.
This again was done using strips and allowing for the rollers on the outside and the threads on the inside.
The gaps where the rollers are I have used a black sharpie.

I have also blacked out the the secondary, again this was done using a sharpie as I was confident enough to start sticking stuff to it.

Next came the one task that I was not looking forward to, the primary mirror.
After looking at it a few time the centre spot looked very much off centre, upon further inspection is seemed to be out by around 2-3mm.
I used two different methods of checking this, the first was drawing around it and then making a centre hole and the second was using a camera. The blue lines in the following image show the true centre and was pretty much in line with my other test (please excuse the VERY dirty mirror).

I set about replacing and also giving the mirror a quick clean (After a LOT of reading and research).

Tomorrow I will be starting to put everything back together and collimating the focuser etc...
I have a larger set of dovetails now as well so will be fitting them so I am able to use the ADM saddle that came with the mount.
A mate of mine is lending me the use of a bench drill so I will also be adding a third screw to the focuser over the weekend and making a new set of adjustable guide scope rings.

Thanks everyone

 

[richyrich_one]

 

You inspired me to check my centre spot posiition and mine appears to be out by a similar amount.

The question is, is 2-3 mm that critical? My first thought is yes but I like things to be spot on.  But if it makes neglible difference then I'd rather not go there.

[richyrich_one]

It's no good it's bugging me already, gonna have to replace it...

[wimvb]

2 hours ago, richyrich_one said:

It's no good it's bugging me already, gonna have to replace it...

Or you could just calculate that in when you collimate. That should work if you have a laser collimator.

[Susaron]

Dear all, some interesting tools to prepare your sessions

http://dso-browser.com/dso/search

http://aladin.u-strasbg.fr/java/nph-aladin.pl?frame=downloading#Description

 

Cheers

[StamosP]

Hello all!

A little story i want to share with you:

I selled both my 130pds and my 200pds (plus the sw coma corrector) a couple of months ago since i wanted to try something different.

So i bought a refractor costing 5-6 times more than the 130...

The results were disappointing (distorted stars) and so i returned the scope to the online store i bought it from, i couldn't accept the fact that my refractor was worse than my cheap newtonian... 

[I already regret that i didn't buy it from FLO (excellent communication plus they offer a checking service)]

I haven't decided yet what i'll do next but there is a big possibilty to buy a 130pds again...

The vfm of this telescope is simply astonishing.

Of course if i will finally proceed i will definitely buy the Baader coma corrector and not the sw one...

[Susaron]

17 minutes ago, StamosP said:

Hello all!

A little story i want to share with you:

I selled both my 130pds and my 200pds (plus the sw coma corrector) a couple of months ago since i wanted to try something different.

So i bought a refractor costing 5-6 times more than the 130...

The results were disappointing (distorted stars) and so i returned the scope to the online store i bought it from, i couldn't accept the fact that my refractor was worse than my cheap newtonian... 

[I already regret that i didn't buy it from FLO (excellent communication plus they offer a checking service)]

I haven't decided yet what i'll do next but there is a big possibilty to buy a 130pds again...

The vfm of this telescope is simply astonishing.

Of course if i will finally proceed i will definitely buy the Baader coma corrector and not the sw one...

Just for curiosity Stamos, which refractor did you buy?.

A colleague has recently received a SW Spirit 100 and he says that the scope optics is from another world.

[StamosP]

It was a SW Esprit 80.

A thread regarding my little adventure: http://www.cloudynights.com/topic/551425-star-testing-the-esprit80/

I also believe that the optics are very good but something was out of alignment (the cell, the focuser, the flattener, who knows...). And unfortunately it isn't an easy job to collimate a refractor.

The overall build quality was impressive (especially the focuser) but i wanted something to work straight out of the box, i think this is the primary reason to buy a refractor...

[richyrich_one]

10 hours ago, Susaron said:

Dear all, some interesting tools to prepare your sessions

http://dso-browser.com/dso/search

http://aladin.u-strasbg.fr/java/nph-aladin.pl?frame=downloading#Description

 

Cheers

Just what I have been looking for. Thanks

[Stub Mandrel]

I posted this in the EQ3 challenge thread as well, but I think its one of my best yet, so please excuse the cross posting:

[Susaron]

I did try something last weekend, when the weather conditions all around were superb, unfortunately I made a silly mistake and the guiding did not work properly. I need to persevere.

Only one 60 secs sub of the double cluster. Apologizes for the quality.

[Stub Mandrel]

HELLO ALL!

If you image using a 130P-DS on a lighter mount, such as an EQ3, you probably use subs of no more than 60 seconds to a minute.

The Alt-Az imagers have recognised the need for some more topics to provide places to discuss the equipment and techniques opened up by more sensitive, lower-noise modern cameras.

We also need more showcase threads, like this, so that instead of telling beginners not to bother trying imaging unless they have masses of expensive kit, they can see the possibilities of imaging on light and alt-az mounts.

If you have a view on this, please share it here:

 

[Stub Mandrel]

HELLO ALL!

If you image using a 130P-DS on a lighter mount, such as an EQ3, you probably use subs of 30 seconds to a couple of minutes.

The Alt-Az imagers have recognised the need for some more topics to provide places to discuss the equipment and techniques opened up by more sensitive, lower-noise modern cameras.

We also need more showcase threads, like this, so that instead of telling beginners not to bother trying imaging unless they have masses of expensive kit, they can see the possibilities of imaging on light and alt-az mounts.

If you have a view on this, please share it here:

[al-alami]

On 8/20/2016 at 14:58, Adam J said:

I use the Orion 50mm finder guider with my QHY5L-II (pictured) it gets the job done just fine at the 130P-DS focal length. I mounted it to the back of the tube to get it to balance, it wont balance if mounted to the front of the tube. I eventually added a 33cm dove tale to move the center of gravity backwards further. I did need a noise piece extension to get focus mind you, Orion designed it with the older guide camera in mind. I have no guiding issues with it, in my opinion the ST80 is just adding more weight for no real guide quality advantage. I can run my setup with a single weight using the finder guider, it would need two with the ST80.

Hi Adam,  Quick question, how did you add a nose piece to the camera? (I assume you meant nose and not noise :p)

[Adam J]

2 hours ago, al-alami said:

Hi Adam,  Quick question, how did you add a nose piece to the camera? (I assume you meant nose and not noise :p)

Yes nose. you need to use a c-mount nose piece extender.

 

[Adam J]

I am still getting extra diffraction spikes despite checking for the spider veins being twisted (they are not). Could it be the focus tube in the light path? I am also getting purple halos on the stars (see below) my camera has an IR filter and the only glass in the system is the MPCC MK3. Could the CLS clip filter be causing this? Some sort of reflection?

Actually looking at it the direction of the extra spike is not the same in all the stars....collimation...tilt?

Btw 24 x 300s 130pds HEQ5 pro

Edited November 6, 2016 by Adam J

[Adam J]

Tried to correct the Halos.

 

Edited November 7, 2016 by Adam J

[Victor Boesen]

2 minutes ago, Adam J said:

Tried to correct the Halos.

wow! that worked out very well. I don't know if it is just me, but it looks like you got the nebula to pop a little more!

Edited November 6, 2016 by Victor Boesen

[Adam J]

7 minutes ago, Victor Boesen said:

wow! that worked out very well. I don't know if it is just me, but it looks like you got the nebula to pop a little more!

Just boosted the blue channel a little. I am going to try and get another 75 frames over the next few weeks.

Edited November 6, 2016 by Adam J

[al-alami]

2 hours ago, Adam J said:

Tried to correct the Halos.

that looks gorgeous ... I can't wait till mine look like that

[Susaron]

15 hours ago, Adam J said:

I am still getting extra diffraction spikes despite checking for the spider veins being twisted (they are not). Could it be the focus tube in the light path? I am also getting purple halos on the stars (see below) my camera has an IR filter and the only glass in the system is the MPCC MK3. Could the CLS clip filter be causing this? Some sort of reflection?

 

 

Hi Adam,

I had the same double reflection spikes, after posting my doubt here I moved back the guiding tube from the original forward finder position to a piggyback set up over a solid dovetail screwed between the rings. My guiding scope weight is around 1 kg (2 pounds), so the torsion moments created on the secondary plus the main camera weight were to much for the thin spiders. Moreover the added dovetail reinforces the stiffness of the whole set-up.

The previous double cluster picture was made with the new set up.

Cheers.

[Adam J]

4 hours ago, Susaron said:

Hi Adam,

I had the same double reflection spikes, after posting my doubt here I moved back the guiding tube from the original forward finder position to a piggyback set up over a solid dovetail screwed between the rings. My guiding scope weight is around 1 kg (2 pounds), so the torsion moments created on the secondary plus the main camera weight were to much for the thin spiders. Moreover the added dovetail reinforces the stiffness of the whole set-up.

The previous double cluster picture was made with the new set up.

Cheers.

I am not sure but I think you are trying to say that the weight attached to the skin of the scope may be causing flex in the tube wall close to the secondary mounting points making them flex?

Problem is that they look straight with everything attached and I am already mounting my finder guider over the rear tube ring. But ill have a look and see. 

[Susaron]

16 minutes ago, Adam J said:

I am not sure but I think you are trying to say that the weight attached to the skin of the scope may be causing flex in the tube wall close to the secondary mounting points making them flex?

Problem is that they look straight with everything attached and I am already mounting my finder guider over the rear tube ring. But ill have a look and see. 

Yes that´s what I meant. as your stars remain centered is not an issue with classical differential flexure but a twist along the optical axis due to the weight of the camera and the 6x30 finder which push in one direction like a corkscrew. Moreover It is highly useful to perform a third balance pointing the scope to the zenith, and assuring the tube does not move in declination, to preserve the balance when pointing the zenith I put the camera and the guide scope at 180 degrees, this has a problem when imaging low latitude objects because the camera can hit the mount, so some care has to be taken.

I will post a picture with my set up later.

Cheers.